Method of and system for maintaining operating performance of a transparency

ABSTRACT

Repair or replacement of a transparency mounted in body of a vehicle, e.g. an aircraft when one or more properties of the transparency is (are) operating outside of an acceptable limit(s) is arranged by monitoring operating performance of a property of the transparency, e.g. by mounted a sensor, e.g. a sensor for detecting moisture; a sensor for detecting impacts and vibrations; a sensor for detecting fractures; a sensor for detecting electric arcing, and a sensor for measuring temperature of an electrically conductive coating, on the transparency. Scheduling repair or replacement of the transparency at a geographical area when the operating performance of the property is outside an acceptable operating performance limit, and forwarding the schedule to the vehicle and to a maintenance location to prepare for the repair or replacement of the transparency at the geographical work area.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/345,932, filed Dec. 30, 2008, which application is related to U.S.patent application Ser. No. 12/345,952 flied Dec. 30, 2008, both ofwhich are herein incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method of and a system for maintainingoperating performance of a transparency, e.g. a vehicle window, and moreparticularly for timely and economically scheduling repair orreplacement of the vehicle window, e.g. an aircraft windshield, whensensor of the windshield indicates that a property of the windshield isperforming outside of an acceptable limit.

2. Discussion of the Presently Available Transparency Technology

Aircraft or aerospace windows, e.g. aircraft windshields include alaminate of plastic layers or sheets, glass layers or sheets andcombinations thereof. The layers of an inner segment of the windshieldface the interior of the aircraft and provide structural stability tothe windshield. The outer segment of the windshield faces the exteriorof the aircraft and usually includes a laminate of glass sheets. Theouter segment of the windshield, which can also provide structuralstability is usually provided with accessories for visual acuity. Forexample and not limiting to the discussion, the outer segment of thewindshield can include an electrically conductive coating, or aplurality of electrically conductive wires, between and connected to apair of spaced bus bars to heat the windshield to prevent the formationof, and/or remove fog and ice on and/or from, respectively, the outersurface of the windshield.

As is appreciated by those skilled in the art, as the service time ofthe aircraft windshield increases, the operating efficiency of thewindshield decreases until such time that the accessories of thewindshield become non-functional, and the windshield needs to bereplaced or repaired. More particularly, the peripheral edge of thewindshield has an outboard moisture seal that is a barrier to preventmoisture from entering between the plastic and glass layers or sheets ofthe windshield. When the seal fails, e.g. cracks and/or the layersde-bond due to erosion caused by wind and rain, moisture enters betweenthe layers of the windshield. While the cracking or de-bonding of theseal is not a structural issue, when moisture reaches inside thewindshield, the windshield can de-laminate, and the conductive coatingor wires, whichever is present can be damaged and fail, thereby reducingthe service life of the windshield. More particularly, when delaminationof the windshield occurs, increased amounts of moisture move between thelayers of the windshield accelerating the degradation of the windshield,e.g. damage and/or failure of the bus bars and electrically conductivecoating or wires reducing or eliminating the defrosting capabilities ofthe windshield.

Untimely response to repair defects in the accessories of thetransparency when they begin, decreases the operating efficiency of thetransparency and can result in the need for emergency maintenance, e.g.transparency repair or replacement. It would be advantageous, therefore,to provide a transparency having sensors to monitor the performance ofthe transparency and a method of acting on the information from thesensors such that repairs, or replacements, of the transparencies isscheduled maintenance and not emergency maintenance.

SUMMARY OF THE INVENTION

This invention relates to a method of arranging repair or replacement ofa transparency when a property of the transparency is operating outsideof an acceptable limit, wherein the transparency is mounted in body of avehicle, the method includes monitoring operating performance of theproperty of the transparency; scheduling repair or replacement of thetransparency at a geographical area when the operating performance ofthe property is outside an acceptable operating performance limit, andforwarding the schedule to the vehicle and to a maintenance location toprepare for the repair or replacement of the transparency at thedesignated geographical work area.

The invention further relates to a system for arranging repair to, orreplacement of, a transparency when a property of the transparency isoperating outside of an acceptable limit, wherein the transparency ismounted in body of a vehicle. The system includes, among other things, asensor to monitor operating performance of the property, and to generatea first signal providing the operating performance of the property, anddata processing equipment to receive the information of the firstsignal, and to generate a second signal scheduling repair or replacementof the transparency at a geographical area when the operatingperformance as indicated by the first signal is outside an acceptableoperating performance limit, wherein the second signal is forwarded tothe vehicle and to a maintenance location to prepare for repair orreplacement of the transparency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a non-limiting embodiment of anaircraft windshield used in the practice of the invention.

FIG. 2 is an isometric view a non-limiting embodiment of a heatingarrangement of the invention.

FIG. 3 is a plan view of a non-limiting embodiment of impact sensors ordetectors positioned on the electrically conductive member of a heatingarrangement in accordance to the teachings of the invention.

FIG. 4 is a non-limiting embodiment of an electrical system of theinvention to monitor and act on output signals of the impact sensorsshown in FIG. 3 in accordance to the teachings of the invention.

FIG. 5 is a schematic view of a non-limiting embodiment of a rupturesensor or detector of the invention.

FIG. 6 is a view taken along lines 6-6 of FIG. 5.

FIG. 7 is a plan view of another non-limiting embodiment of a rupturesensor or detector of the invention.

FIG. 8 is a plan view of non-limiting embodiment of a sensor or detectorto monitor the temperature of the electrically conductive member of aheating arrangement in accordance to the teachings of the invention.

FIG. 9 is a non-limiting embodiment of an electrical system to monitorand act on the output signals of the sensor shown in FIG. 8 inaccordance to the teachings of the invention.

FIG. 10 is a non-limiting embodiment of an electrical system of theinvention for measuring the voltage output of a bus bar of the heatingarrangement shown in FIG. 8 to monitor the temperature of theelectrically conductive member of the heating arrangement in accordanceto the teachings of the invention.

FIG. 11 is a plan view of another non-limiting embodiment of a sensor tomeasure the temperature of the electrically conductive member of aheating arrangement in accordance to the teachings of the invention.

FIG. 12 is a plan view of a non-limiting embodiment of a moisture sensoror detector positioned over the electrically conductive member of aheating arrangement in accordance to the teachings of the invention.

FIG. 13 is a non-limiting embodiment of an electrical system formonitoring the output of the moisture sensors shown in FIG. 12 inaccordance to the teachings of the invention.

FIG. 14 is a view taken along lines 14-14 of FIG. 12.

FIG. 15 is a side elevated view of another non-limiting embodiment of amoisture sensor positioned on the electrically conductive member of aheating arrangement in accordance to the teachings of the invention.

FIG. 16 is a view similar to the view of FIG. 14 showing anothernon-limiting embodiment of a moisture sensor or detector on a sheet ofthe windshield shown in FIG. 2 in accordance to the teachings of theinvention.

FIG. 17 is a plan view of another non-limited embodiment of a moisturesensor or detector that can be used in the practice of the invention.

FIG. 18 includes FIGS. 18A and 188. FIG. 18A is a non-limitingembodiment of a schematic of a system of the invention for monitoringthe output signals of sensors or detectors in accordance to theteachings of the invention to monitor the real time performance offeatures, properties, or characteristics of accessories that provide theaircraft transparency with visual acuity, and FIG. 18B is a schematic ofa system for scheduling repairs to, or replacements of, aircrafttransparencies that the signals of the sensors or detectors indicate areperforming outside of acceptable limits.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, spatial or directional terms such as “inner”, “outer”,“left”, “right”, “up” “down”, “horizontal”, “vertical”, and the like,relate to the invention as it is shown in the drawing on the figures.However, it is to be understood that the invention can assume variousalternative orientations and, accordingly, such terms are not to beconsidered as limiting. Further, all numbers expressing dimensions,physical characteristics, and so forth, used in the specification andclaims are to be understood as being modified in all instances by theterm “about”. Accordingly, unless indicated to the contrary, thenumerical values set forth in the following specification and claims canvary depending upon the property desired and/or sought to be obtained bythe present invention. At the very least, and not as an attempt to limitthe application of the doctrine of equivalents to the scope of theclaims, each numerical parameter should at least be construed in lightof the number of reported significant digits and by applying ordinaryrounding techniques. Moreover, all ranges disclosed herein are to beunderstood to encompass any and all subranges subsumed therein. Forexample, a stated range of “1 to 10” should be considered to include anyand all subranges between and inclusive of the minimum value of 1 andthe maximum value of 10; that is, all subranges beginning with a minimumvalue of 1 or more and ending with a maximum value of 10 or less, e.g.,1 to 67, or 3.2 to 8.1, or 5.5 to 10. Also, as used herein, the term“positioned over” or “mounted over” means positioned on or mounted overbut not necessarily in surface contact with. For example, one article orcomponent of an article “mounted over or positioned over” anotherarticle or component of an article does not preclude the presence ofmaterials between the articles, or between components of the article,respectively.

Before discussing several non-limiting embodiments of the invention, itis understood that the invention is not limited in its application tothe details of the particular non-limiting embodiments shown anddiscussed herein since the invention is capable of other embodiments.Further, the terminology used herein to discuss the invention is for thepurpose of description and is not of limitation. Still further, unlessindicated otherwise, in the following discussion like numbers refer tolike elements.

Non-limiting embodiments of the invention will be directed to anaircraft laminated transparency, and in particular to an aircraftwindshield; the invention, however, is not limited to any particulartype of aircraft transparency, and the invention contemplates thepractice of the invention on aircraft windows of the type having amedium responsive to electric stimuli to increase or decrease visibletransmission, e.g. but not limited to the type of window disclosed inU.S. Published Patent application 2007/0002422A1 and on aircraft windowsof the type having an insulated air space between a pair of laminatedsheets. The entire disclosure of the publications is hereby incorporatedby reference. Further, the invention can be practiced on commercial andresidential windows, e.g. but not limited to type disclosed in U.S. Pat.No. 5,675,944, which patent in its entirety is hereby incorporated byreference; a window for any type of land vehicle; a canopy, cabin windowand windshield for any type of air and space vehicle, a window for anyabove or below water vessel, and a window for a viewing side or door forany type of containers, for example but not limited to a refrigerator,cabinet and/or oven door. Still further, the invention is not limited tothe material of the layers or sheets of the transparency, and the layersor sheets can be made of, but not limited to, cured and uncured plasticsheets; annealed, heat strengthened, and heat and chemicallystrengthened, clear, colored, coated and uncoated glass sheets. Stillfurther the invention can be practiced on windows having opaque sheets,e.g. but not limited to wood and metal sheets, and glass sheets havingan opaque coating, and combinations thereof.

Shown in FIG. 1 is a non-limiting embodiment of an aircraft windshield20 that can be used in the practice of the invention. The windshieldincludes a first glass sheet 22 secured to a second glass sheet 24 by afirst interlayer 26; the second sheet 24 secured to a secondvinyl-interlayer or sheet 28 by a first urethane interlayer 30, and thesecond vinyl-interlayer 28 secured to a heatable member 32 by a secondurethane interlayer 34. An edge member or moisture barrier 36 of thetype used in the art, e.g. but not limited to a silicone rubber or otherflexible durable moisture resistant material is secured to (1)peripheral edge 38 of the windshield 20, i.e. the peripheral edge 38 ofthe first and second sheets 22, 24; of the first and secondvinyl-interlayers 26, 28; of the first and second urethane interlayers30, 34 and of the heatable member 32; (2) margins or marginal edges 40of outer surface 42 of the windshield, i.e. the margins 40 of the outersurface 42 of the first glass sheet 22 of the windshield 20, and (3)margins or marginal edges 44 of outer surface 46 of the windshield 20,i.e. margins of the outer surface 46 of the heatable member 32.

As is appreciated by those skilled in the art and not limiting to theinvention, the first and second glass sheets 22, 24; the first andsecond vinyl-interlayers 26, 28 and the first urethane interlayer 30form the structural part, or inner segment, of the windshield 20 and theouter surface 42 of the windshield 20 faces the interior of the vehicle,e.g. an aircraft 47 (shown only in FIG. 18B), and the second urethanelayer 34 and the heatable member 32 form the non-structural part, orouter segment, of the windshield 20, and the surface 46 of thewindshield 20 faces the exterior of the aircraft. The heatable member 32provides heat to remove fog from, and/or to melt ice on, the outersurface 46 of the windshield 20 in a manner discussed below.

As can be appreciated the invention is not limited to the constructionof the windshield 20 and any of the constructions of aircrafttransparencies used in the art can be used in the practice of theinvention. For example and not limited to the invention, the windshield20 can include a construction wherein the vinyl interlayer 28 and theurethane interlayer 30 are omitted, and/or the sheets 22 and 24 areplastic sheets.

Generally the glass sheets 22, 24 of the windshield 20 are clearchemically strengthened glass sheets; however, the invention is notlimited thereto, and the glass sheets can be heat strengthened or heattempered glass sheets. Further as is appreciated, the invention is notlimited to the number of glass sheets, vinyl interlayers or urethaneinterlayers that make up the windshield 20 and the windshield 20 canhave any number of sheets and/or interlayers.

The invention is not limited to the design and/or construction of theheatable member 32, and any electrically conductive heatable member usedin the art to heat a surface of a sheet to melt ice on, and/or removefog from the surface of the sheet can be used in the practice of theinvention. With reference to FIG. 2, in one non-limiting embodiment ofthe invention, the heatable member 32 includes a glass sheet 60 having aconductive coating 62 applied to surface 64 of the glass sheet 60, and apair of spaced bus bars 66, 68 in electrical contact with the conductivecoating 62. The invention is not limited to the composition of theconductive coating 62, for example and not limiting to the invention theconductive coating 62 can be made from any suitable electricallyconductive material. Non-limiting embodiments of conductive coatingsthat can be used in the practice of the invention include, but are notlimited to a pyrolytic deposited fluorine doped tin oxide film of thetype sold by PPG Industries, Inc. under the trademark NESA®; a magnetronsputter deposited tin doped indium oxide film of the type sold by PPGIndustries, Inc under the trademark NESATRON®; a coating made up of oneor more magnetron sputter deposited films, the films including, but notlimited to a metal film, e.g. silver between metal oxide films, e.g.zinc oxide and/or zinc stannate, each of which may be appliedsequentially by magnetron sputtering, e.g. as disclosed in U.S. Pat.Nos. 4,610,771; 4,806,220 and 5,821,001 the disclosures of which intheir entirety are hereby incorporated by reference.

As can be appreciated, the invention is not limited to the use of anelectrically conductive coating to heat the glass sheet 60 andcontemplates the use of any type of member that can be electricallyheated, e.g. but not limited to electrical conducting wires. The wires,e.g. the wires 69 shown in phantom in FIG. 1 can be embedded in theinterlayer 34 and electrically connected to the bus bars 66 and 68. Sucha heating arrangement is known in the art under the PPG Industries OhioInc, registered trademark AIRCON and is disclosed in U.S. Pat. No.4,078,107, which patent in its entirety is incorporated herein byreference.

The invention is not limited to the design and/or construction of thebus bars and any of the types of bus bars used in the art may be used inthe practice of the invention. Examples of bus bars that can be used inthe practice of the invention, include, but not limited to, the typesdisclosed in U.S. Pat. Nos. (fired on silver ceramic glass frit);4,623,389; 4,894,513; 4,994,650, and 4,902,875, which patents in theirentirety are hereby incorporated by reference. In the preferred practiceof the invention, the bus bars are fired on silver ceramic glass frit,e.g. of the type disclosed in U.S. Pat. No. 4,623,389. Each of the busbars 66 and 68 are connected by a wire 70 and 71 respectively to a powersource 72, e.g. a battery to flow current through the bus bars 66 and68, and the conductive coating 62 to heat the conductive coating 62 andsheet 60 to remove ice and/or fog from the surface 46 of the windshield20. An on-off switch, a rheostat or variable transformer 73 is connectedto one of the wires, e.g. between the wire 71 between the positions 71Aand 71B to position the rheostat between the power source 72 and the busbar 68 to vary or regulate the current flow through the bus bars 68 and66, and the conductive coating 62 to control the temperature of theconductive coating 62. Although not limiting to the invention, ends 75of the bus bar 66, and ends 76 of the bus bar 68 are spaced fromadjacent sides 78-81 of the glass sheet 60 to prevent arcing of the busbars 66 and 68 with the metal body cover of the aircraft 47 (shown onlyin FIG. 18B).

The discussion is now directed to the placement of sensors or detectorson selected components of the windshield 20, to monitor the performanceof the selected components of the windshield 20, in accordance to theteachings of the invention.

Impact Sensor

In one non-limiting embodiment of the invention, the windshield 20 isprovided with an impact sensor or detector that generates a signal whenan object hits or impacts the windshield, e.g. but not limiting to theinvention, hits the outer surface 46 of the windshield 20. For exampleand not limiting to the invention, as the aircraft travels down a runwayduring take-off or landing, foreign objects. e.g. stones are propelledthrough the air and can hit the outer surface 46 of the windshield. Theimpact detector mounted a sheet of the windshield can be used toindicate that one or more foreign objects have hit the windshield, andoptionally the location on the outer surface 46 where the hit or impactoccurred and the relative energy of the impact on the surface 46 of thewindshield 20.

With reference to FIG. 3, in one non-limiting embodiment of theinvention, one or more impact sensors or detectors (four detectors 83A,83B 83C and 83D are shown in FIG. 3) are mounted adjacent each one ofthe skies 78-81 of the glass sheet 60. In this non-limiting embodimentof the invention, each of the impact detectors include a piezoelectricmaterial, e.g. but not limited to a piezoelectric crystal. When thepiezoelectric material is exposed to vibration, e.g. vibration of theglass sheet 60 (see FIGS. 1 and 2) caused by a stone hitting the outersurface 46 of the glass sheet 60, the piezoelectric material undergoes acompression or distortion and, as a result, produces an electric field,which can be used to activate or to cause an alarm and/or a recorder tobe activated to announce and/or record the hit or impact. Further, usingthree or more impact detectors the location of the impact on the surface46 of the windshield can be identified, as discussed below.

With reference to FIGS. 3 and 4 as needed, there is shown the heatablemember 32 having one of the impact detectors 83A-D mounted adjacent oneof the sides 78-81, respectively of the glass sheet 60. The detectors83A-D are mounted on the conductive coating 62 and have one electricalcontact of the detectors 83A-D electrical connected to the conductivecoating 62 and the other electrical contact of each of the detectors83A-D connected by a wire 84A-D, respectively, to a rheostat or variabletransformer 85A-D, respectively. Each of the rheostats 85A-D areelectrically connected to the console 88 and the positive pole of thepower supply 72 by way of wires 86A-D, respectively (see FIG. 4). Inthis manner, the power to the detectors 83A-D is provided by the powersupply 72, controlled by the rheostats 85A-D, respectively and changesin the electric field of each of the impact detectors 83A-D measured ormonitored by the comparator in the console 88. As can be appreciated theinvention is not limited to the manner in which power is provided to thedetectors 83A-D and any circuit arrangement can be used in the practiceof the invention, e.g. and not limiting to the invention one electricalcontact of the detectors 83A-D can be mounted on any one or more of thesheets of the windshield and directly connected to one pole of a powersupply dedicated to providing electrical power to the detectors and theother contact of the detectors 83A-D connected to the other pole of thededicated power supply. As can be appreciated, the invention is notlimited to the type of power supply used in the practice of theinvention and the power supply can generate alternating or directcurrent.

With the arrangement shown in FIGS. 3 and 4, the piezoelectric materialof the detectors 83A-D undergoes a compression or distortion when thewindshield is vibrated, e.g. an object hits the outer surface 46 of thewindshield 20. The vibration of the piezoelectric crystal of thedetectors produces an electric field or current which is sent along oneor more of wires 84A-D of the detectors 83A-D, respectively to theconsole 88 (see also FIG. 18A). The console 88 is provided with dataprocessing equipment, e.g. software which analysis the signal forwardedalong wires 86A-D to determine the location of the impact bytriangulation of the signals from selected ones or all of the detectors83A-D, and the magnitude of the impact, e.g. by the magnitude of theelectric field, and stores the information. Electronic circuitry forelectric file of impact detectors, e.g. piezoelectric crystal is wellknown in the art, e.g. see U.S. Pat. No. 6,535,126, which patent in itsentirety is hereby incorporated by reference, and no further discussionis deemed necessary. In another non-limiting embodiment of theinvention, signals from the detectors 83A-D that exceed a predeterminedamount of current are displayed on the console 88 to indicate that avisual inspection of the outer surface 46 of the windshield 20 should bemade, and/or the windshield repaired, e.g. at the next scheduled stop ofthe aircraft, and optionally can be forwarded to a control center in amanner discussed below to schedule any needed repairs.

As is appreciated, aircrafts during take-off, in-flight and landingvibrate which causes the impact detectors to vibrate and generate theelectric field. The rheostats 85A-85D or electronic filters can be usedto pass only electric fields above a predetermined level. In thismanner, the impact detector can be used to detect impacts to thewindshield and to provide a performance log on the vibration of theaircraft.

Rupture Sensor

In the following discussion, the rupture or crack detector, or sensordisclosed in U.S. Pat. No. 6,794,882, the entire disclosure of which ishereby incorporated by reference, will be used in the practice of theinvention, however, as is appreciated, the invention is not limitedthereto and any of the crack sensors or detectors known in the art canbe used in the practice of the invention. A non-limiting embodiment of arupture sensor or detector of the type disclosed in U.S. Pat. No.6,794,882 is shown in FIG. 5 and designated by the number 89. The cracksensor 89 includes an electrically conductive strip 90 extending alongor around substantially the entire outer periphery 38 (see FIG. 1) of amajor surface of one of the sheets 22, 24, 28 and 60 of the windshield20. In FIGS. 5 and 6, the conductive strip 90 is shown mounted over theelectrically conductive layer 62 of the glass sheet 60, surrounds thebus bars 66 and 68, and electrically isolated from the conductivecoating 62 by an electrically insulating layer 96, e.g. a urethane layeror an electrically non-conductive coating layer.

The conductive strip 90 is mounted on the conductive coating 62 spacedfrom the sides 78-81 of the sheet 60 as shown in FIG. 5. As can beappreciated, the conductive strip 90 can decrease visibility throughthat portion of the glass sheet over which it is deposited, andtherefore, the maximum width of the conductive strip 90 depends upon therequired or specified operator viewing area through the windshield 20.Aircraft transparencies, e.g. windshields have specific safetyrequirements specifying the viewable (or transparent) area required.However, if the conductive strip 90 is formed from a substantially orfully transparent material that still has the required conductiveproperties, the placement of the conductive strip 90 with respect to thesheets of the windshield would be highly variable. For example, and notlimiting to the invention, the conductive strip 90 can form an inner orsmall strip or band more centrally located on the surfaces of thesheets. Alternatively, the conductive member 90 can include multiple andconcentric strips or bands emanating from a center of the glass sheetsoutwardly towards the periphery 38 of the sheets 22, 24, 28 and 60.Alternatively still, the conductive strip 90 can be in the form of an“X” or other shape, depending upon the anticipated nature and course ofa rupture or break in the sheets.

As discussed above, the conductive coating 62 is electrically isolatedfrom the conductive strip 90 by an electrically insulating layer 96. Ascan be appreciated, the insulating layer 96 can mask the presence of asmall crack in the glass sheet 32 by preventing the conductive strip 90from separating. This limitation is eliminated by applying theconductive strip 90 on an uncoated surface portion of the glass sheet60, e.g. and not limiting to the invention, by surrounding the coating62 and the bus bars 66 and 68 with a strip of uncoated glass 92 (shownonly in FIG. 2). The uncoated glass strip 92 can be provided in anyconvenient manner, e.g. by masking the glass surface during the coatingprocess, or abrasively or chemically removing the coating from the glasssurface. Because the glass is chemically strengthened it is preferred tomask the areas during the coating process to avoid surface damage thatcan cause the tempered glass to fracture.

As can be appreciated, the conductive strip 90 can be applied to anysurface of any one of the sheets of the laminated windshield 20;however, in the preferred practice of the invention the conductive strip90 is preferably between the sheet the uncoated portion 92 of the sheet60 and the urethane layer 34. In the non-limiting embodiment shown inFIG. 6, the conductive strip 90 is mounted over the uncoated portion 92of the sheet 60 (see FIG. 2) and extends around substantially the entireouter periphery of the coating layer 62. The conductive strip 90 has afirst termination surface 104 and a second termination surface 106. Thedistance or gap between the first termination surface 104 and the secondtermination surface 106 should be sufficient to prevent any descriptiveelectrical field communication between the termination surfaces 104 and106.

The rupture sensor 90 further includes an electrical power source 108 inelectronic communication with the conductive strip 90 to apply anelectrical potential to the conductive strip 90. The power source 108can be any conventional electrical source, such as, but not limited to,a battery, an electrical generator, and the like. Further, the rupturesensor 90 includes an electrical measurement mechanism 110, such as anohmmeter, in communication with the conductive strip 90 for measuringthe electrical potential of the conductive strip 90. A control mechanism112, such as a software and a computer, is used to control andcommunicate with both the electrical power source 108 and the electricalmeasurement mechanism 110. This control mechanism 112 can be used tocommand the electrical power source 108 to provide a predetermined orspecifically set electrical potential to the conductive strip 89 and,after application, the control mechanism 112 can collect and/orcalculate the electrical potential of the conductive strip 90 via theelectrical measurement mechanism 110. All of the electrical power source108, the electrical measurement mechanism 110 and the control mechanism112 can be combined in a single unit or instrument, e.g. the console 88(see FIG. 18) or can be individual units (see FIG. 5).

The electrical power source 108 applies a set voltage to the conductivestrip 90, as set or specified by the control mechanism 112. This setvoltage allows current to flow through the conductive strip 90. Theelectrical measurement mechanism 110 is connected to the conductivestrip 90 through a first lead 114 and a second lead 116. The first lead114 is connected to the first termination surface 104 and the secondlead 116 is connected to the second termination surface 106. Thisconnection allows the conductive strip 90 to act as an electricalcircuit when the electrical power source 108 applies an electricalpotential.

The electrical measurement mechanism 110 reads or measures the currentflowing through the conductive strip 90 via the first lead 114 connectedto the first termination surface 104, and the second lead 116 connectedto the second termination surface 106. Since the electrical power source108 is applying a set voltage, and the electrical measurement mechanism110 is reading or measuring the current flowing through the conductivestrip 90, the electrical measurement mechanism 110 (or the controlmechanism 112) is able to calculate the resistance value of theconductive strip 89.

When a rupture or crack occurs and propagates in the glass sheet 60, itwill eventually reach the conductive strip 90. As the crack begins tomove through and break a section of the conductive strip 90, theresistance value calculated by either the electrical measurementmechanism 110 or the control mechanism 112 begins to increase. Thisresistance value increase indicates a rupture or crack in the glasssheet 60. When the crack fully traverses and breaks the conductive strip90, the resistance value reaches infinity and indicates a seriousrupture condition.

The conductive strip 90 can be a conductive coating material formed fromany suitable electrically conductive material, such as a metal, metaloxide, a semi-metal, an alloy, or other composite material. Theconductive strip 90 can also be opaque or transparent. Further, theconductive strip 90 can be a conductive coating material formed from aceramic paint or electrically conductive ink. The conductive materialmust be a material that will crack or separate when the glass sheetcracks or must otherwise change its electrical properties in a mannerthat allows for detection of a change. The conductive strip 90 can bedeposited on a surface of one or more of the glass sheets 22, 24, 28 and60 through conventional thin film deposit methods or conventional thickfilm deposit methods; conventional adhesion manufacturing methods;screening, or other similar process. In one embodiment, the conductivemember 90 is a conductive indium tin oxide coating.

The invention contemplates applying a conductive strip on more than onesheet, e.g. but not limiting to the invention, applying a conductivestrip 90 on a surface of the glass sheets 22, 24, 28 and 60. As isappreciated, when a conductive strip is placed on more than one sheets,each one of the conductive strips 90 has it own electrical power source108, or one power source is provided and is electrically connected totwo or more of the conductive strips 90 and a rheostat is provided foreach conductive strip 90 for controlling voltage to each of theconductive strips 90 in a manner discussed above for the impact sensors83A-D, and discussed below for the rupture sensor. Similarly, one ormultiple electrical measurement mechanisms 110 can be used to read andmeasure the electrical potential or current flowing through each of theconductive strips 90 on the sheets 22, 24, 28 and 60 of the windshield20. In this manner the condition of each of the glass sheets 22, 24, 28and 60 can be monitored.

The control mechanism 112 and/or the central or multiple dedicatedelectrical measurement mechanisms 110 are equipped to identify eachindividual conductive strip 90 on a glass sheet 22, 24, 28 and 60 andcalculate the electrical potential (resistance value) for eachconductive strip 90. In this manner, the vehicle operator receives anindication from the alarm mechanism 118 of the existence and extent of arupture in each of the glass sheets 22, 24, 28 and 60 due to thebreaking or bridging of the associated conductive strip 90. As can beappreciated, during a rupture condition, it typically proves difficultto decipher which glass sheet has been ruptured or cracked, andproviding a conductive strip 90 on each of the sheets 22, 24, 28 and 60allows the vehicle operator to identify the sheet that has the failurecondition.

The conductive strip 90 can be embedded in the interlayers 26, and 34between the sheets 22, 24, 28 and 60 as long as the conductive strip 90is in contact with its respective one of the sheets 22, 24, 28 or 60 ina manner that will break or disrupt the conductive strip 90 in the eventthe surface of the glass sheet having the conductive strip cracks. Inorder to enhance identifying the rupture location on the surface,multiple conductive strips 90 can be placed in a grid or array patternover the major surface of the sheets, or optionally an array pattern canbe used adjacent the periphery 38 of the sheets as shown in FIG. 7 so asnot to minimize reducing the vision area of windshield 20.

In the non-limited embodiment of the invention shown in FIG. 7, each oneof sides 120-123 of glass sheet 125 has two rows 132 and 134 ofconductive stripes at or adjacent margin 135 of glass sheet 125 toprovide an array of conductive stripes to more definitively identifywhere a rupture or crack in the sheet 126 has occurred. Moreparticularly, the first row 132 of conductive stripes includesconductive stripes 136-139 at the corners 141-144, respectively of thesheet 125, and conductive strips 146 and 147 at the sides 121 and 123,respectively of the sheet 125. With continued reference to FIG. 7, end136A of the strip 136 is adjacent to and spaced from end 139B of thestrip 139 at the side 120 of the sheet 125; end 136B of the strip 136 isspaced from and adjacent to end 146A of the strip 146, and end 146B ofthe strip 146 is adjacent to and spaced from end 137A of the strip 137,at the side 121 of the sheet 125; end 137B of the strip 137 is adjacentto and spaced from the end 138A of the strip 138 at the side 122; end138B of the conductive strip 138 is adjacent to and spaced from end 147Aof the strip 147, and end 147B of the strip 147 is adjacent to andspaced from end 139A of the strip 139, at the side 123, of the sheet125.

The second row 134 of the conductive strips includes conductive strips150-153. The conductive strip 160 extends between sides 121 and 123 ofthe glass sheet 125; has its end 150A adjacent to and spaced from end151B of the strip 161, and its end 150B adjacent to and spaced from end153A of the strip 153. The conductive strip 151 extends between sides122 and 120 of the glass sheet 125 and has its end 151A adjacent to andspaced from end 152B of the strip 152. The conductive strip 152 extendsbetween sides 121 and 123 of the glass sheet 125 and has its end 152Aadjacent to and spaced from end 153B of the strip 153. The conductivestrip 153 extends between sides 120 and 122 of the glass sheet 125 andhas its end 153B adjacent to and spaced from end 152A of the strip 152.

The ends A and B of each of the strips 136-139, 146, 147 and 150-153 areindividually electrically connected to the electrical power source 108(see FIG. 5) to apply an electrical potential to the conductive strips136-139, 146, 147 and 150-153, and to the electrical measurementmechanism 110 for measuring the electrical potential of the conductivestrips 136-139, 146, 147 and 150-153. The control mechanism 112 controlsand communicates with both the electrical power source 108 and theelectrical measurement mechanism 110 as discussed above to command theelectrical power source 108 to provide a predetermined or specificallyset electrical potential to the conductive strips 136-139, 146, 147 and150-153 and, after application, the control mechanism 112 can collectand/or calculate the electrical potential of the conductive strip136-139, 146, 147 and 150-153 via the electrical measurement mechanism110. All of the electrical power sources 108, the electrical measurementmechanisms 110 and the control mechanisms 112 for the conductive stripes136-139, 146, 147 and 150-153 can be combined in a single unit orinstrument, e.g. the console 88 (see FIG. 13) or can be individualunits.

With continued reference to FIG. 7, the arrangement of two rows 132 and134 each having spaced conductive strips, e.g. stripes 136-139, 146 and147 in row 132, and the conductive stripes 150-153 in the row 134provides for a closer approximation of the position of the crack orbreak in the glass sheet. More particularly and not limiting to theinvention, crack 156 fractures the conductive strips 146 and 151,positioning the crack 156 in the center area of the side 121 of thesheet 125; crack 158 fractures the conductive strips 139 and 153,positioning the crack 158 in the side 123 adjacent the side 138 of thesheet 125. As can be appreciated the arrangement of the conductivestrips as shown in FIG. 5 is useful, but not limited to, a study todetermine if cracks are a random event or caused by stress imposed onthe edges of the windshield by the design of the frame securing thewindshield 20 in the body of the aircraft,

Arcing Sensor or Detector

The discussion is now directed to non-limiting embodiments of theinvention for monitoring the performance of the heating arrangementwhich includes the bus bars 66, 68 and the electrically conductivemember, e.g. the electrically conductive coating 62, or wires embeddedin the interlayer 34 to determine the occurrence of, or a highprobability of the occurrence of, arcing indicating that the windshieldshould be repaired, or replaced before the windshield is damaged byarcing, or before arcing occurs, respectively. Arcing of interest in thepresent discussion, but not limited thereto is electric arcing over acrack in the coating 62 and/or bus bars 66 and 68, and/or separation ofthe bus bars 66, 68 and/or coating 62. As is appreciated by thoseskilled in the art, impacts to the glass sheet 60 of the heatable member32 can result in fractures in the glass sheet 60 that result infractures in the coating 62. Further, moisture moving through themoisture barrier 36 of the windshield 20 (see FIG. 1) can causedelamination of the laminated windshield. The delamination of thewindshield can result in separation of one or both of the bus bars 66and 68 from the conductive coating, or the wires embedded in theinterlayer 38. The electric arcing over cracks in the conductive coating62 and separations between the bus bars and the coating result in spotheating which can increase sufficiently to cause the glass 60 of theheatable member 32 to fracture.

With reference to FIGS. 8 and 9 there is shown a non-limiting embodimentof another heating member of the invention identified by the number 160.The heating member 160 includes the bus bars 66 and 68 electricallyconnected to the conductive coating 62 on the glass sheet 60 (sheet 60shown in FIGS. 1 and 2). As previously discussed, the voltage to theconductive member 62 is provided by current moving from the power source72 through the wire 71 and the switch or rheostat 73, to the end 76 ofthe bus bar 68, through the bus bar 68 and the coating 62 to the bus bar66, through the wire 70 at the end 75 of the bus bar 66 to the powersource 72 (see also FIG. 2). With reference to FIGS. 8 and 9 as needed,arcing sensor or detector 164 includes a comparative circuit 165 havinginput side connected to opposite end 166 of the bus bar 68 by a wire167, and connected to the current input wire 71, which is connected tothe end 76 of the bus bar 68 (see also FIG. 2). In operation, areference voltage is provided to the comparator circuit 165 by the wire71 connected to the end 76 of the bus bar 68.

The electrical power flows through the wire 71 to the bus bar 68,through the conductive coating 62 to the opposite bus bar 66. A portionof the power passing through the bus bar 68 is directed by the wire 167at the end 166 of the bus bar 68 to the comparative circuit 166. Thecomparator circuit 165 continuously or periodically compares thereference voltage from the wire 71 to the measured voltage of the wire167. When the measured voltage of the wire 167 differs from thereference voltage by a predetermined amount, an output signal from wirelead 168 of the comparator 165 is generated which can terminate thepower being supplied to the bus bars and/or send a status report of theperformance of the heatable member 160 in a manner discussed below. Moreparticularly, if the measured voltage from the wire 167 decreases it canbe an indication that current is not moving through the bus bar 68. Ifthe measured voltage from the wire 167 increases, it can be anindication that the current moving through the bus bar 68 has increased,possibly as a result of an increase in the resistance of the conductivecoating 62, or the bus bar 66, e.g. caused by a crack in the conductivecoating 62, or one or both of the bus bars 66, 68. As is appreciated thesensor 164 does not have the capability of identifying what is causingan increase or decrease in the voltage measured at the end 166 of thebus bar 68, however, an increase above a high norm value, or a decreasebelow a low norm value is an indication that the performance of theheatable member 160 is changing and that remedial action, e.g.discontinue the electrical power input to the heating arrangement,making a repair to the heatable member 160, or a replacing thewindshield 20, should be taken. As can be appreciated, the comparativecircuit 164 can be mounted in the console 88 (see FIG. 18A).

The sensor 164 is of the type disclosed in U.S. Pat. No. 4,902,875 theentire disclosure of which is hereby incorporated by reference. As isappreciated, the invention is not limited to the type of sensordisclosed in U.S. Pat. No. 4,902,875, and any sensor that measures thevoltage or current of the conductive member 32 (see FIG. 2) or 160 (seeFIG. 8) to indicate changes in the voltage or current passing throughbus bars 66, 68 and/or conductive coating 62 of the conductive member 32or 160 can be used in the practice of the invention.

With reference to FIGS. 8 and 10, as needed there is shown anothernon-limiting embodiment of a sensor designated by the number 170 thatcan be used can be used in the practice of the invention to measure thetemperature of the conductive coating 62 and prevent over heating of theheatable member of the windshield 20. The sensor 170 is of the typedisclosed in U.S. Pat. No. 4,994,650, the entire disclosure of which ishereby incorporated by reference. As is appreciated, the invention isnot limited to the type of sensor disclosed in U.S. Pat. No. 4,994,650and any sensor that measures the temperature of a conductive surface toprevent over heating of the conductive surface can be used in thepractice of the invention.

The sensor 170 is an electric field detector that is electricallyconnected with the coating 62 to monitor the coating voltage at apredetermined location between bus bars 66 and 68. The sensor 170 isconnected to a voltage comparative system 171 by way of wire 172.Although not limiting in the present invention, in the particularembodiment of the invention illustrated in FIG. 8, the position of thesensor 170 is spaced in close proximity to the bus bar 68 and is in theupper corner of the conductive member 160 so that its presence isminimized when viewing through the windshield 20. As is appreciated, theposition of the sensor 170 can be selected to be at other locationsbetween bus bars 66, 68, and can also extend into the viewing area ofthe windshield 20, if permissible.

With continued reference to FIGS. 8 and 10, the voltage comparator 171is connected to the power source 72 by wire 174. In principle, whenpower is applied to the bus bars 66, 68, an electric field isestablished in the conductive coating 62 between the bus bars 66, 68.The voltage within the electric field is fairly linearly distributedsuch that a voltage at a particular location in the coating 62 isproportional to the physical location of that particular locationrelative to the bus bars. For a given location, if the applied voltagechanges, the voltage at that given location will change proportionally.As a result, when a predetermined amount of change in the coatingvoltage is determined, it can be assumed that a current to the bus barsis discontinued or there is a reduction of current through the bus barsdue to increased resistance of the bus bars. The increased resistancecan be due to a discontinuity, i.e. break in the bus bar or a crack inthe conductive coating. In this manner, the electric field detector 170operates to detect a break in the bus bars and/or conductive coating bymonitoring the voltage in the coating 62 at the position of the sensor170. Although not limiting in the present invention, for the purpose ofthe following discussion, the current flows through the coating 62 fromthe bus bar 68 to the bus bar 66 so that the voltage drop within thecoating 62 is from the bus bar 68 to the bus bar 66.

In the particular non-limiting embodiment illustrated in FIGS. 8 and 10,a reference voltage is provided to the comparator 171 from the powersource 72 through the wire 174. The current flows through the bus bar68, and through the coating 62 to the bus bar 66. A circuit of thecomparator 171 monitors the voltage of the coating 62. The comparator171 continuously compares the reference voltage from the power source 72to the measured voltage of the coating 62 via the detector wire 172.When the measured voltage from the detector wire 172 differs from thereference voltage by a predetermined amount, an output signal from thecomparator 171 is sent through lead 176 to the console 88. Thedifference in the voltage is indicative of that amount of a shift in theperformance of the bus bars 66, 68 and/or coating 62, e.g. due to abreak in the bus bars, a separation of the bus bars and coating, and/ora crack in the coating 62. The console 88 analysis the informationreceived from the comparator 171 and takes appropriate action whichincludes but is not limited to, terminate the power input to the bus bar68, or indicate that the performance of the coating 62 and/or bus bars66 and/or 68 of the conductive member 160 has changed and thatmaintenance or repair is or will be needed to prevent arcing andassociated localized overheating of the conductive member 62.

As can be appreciated, the comparator 165 (FIG. 9) and/or 171 (FIG. 10)can be included in the circuitry of the console 88, or can be individualor combined systems outside of the console 88.

Conductive Coating Temperature Sensor

With reference to FIG. 11, there is shown a sensor or detectoridentified by the number 200 that can be used to measure the temperatureof the conductive coating 62 of the heatable member 32 to prevent overheating of the heatable member. The sensor 200 is of the type disclosedin U.S. Pat. No. 4,894,613 the entire disclosure of which is herebyincorporated by reference. As is appreciated, the invention is notlimited to the type of sensor disclosed in U.S. Pat. No. 4,894,513, andany sensor that measures the temperature of an electrically conductivemember can be used in the practice of the invention.

With continued reference to FIG. 11, the temperature sensor 200 of thisnon-limiting embodiment of the invention includes one or more wireloops, e.g. and not limiting to the invention, the sensor 200 shown inFIG. 11 has wire loops 202-206. As is appreciated, the invention ispracticed with the sensor 200 having any number of wired loops. If onlyone wire loop is used, it preferably extends within the conductivecoating 62 to a position where, based on the conductive member designand/or experience, a hot spot is anticipated. Each of the wire loops202-206 is a resistance type device, i.e., its resistance changes as itstemperature changes. Although not limiting in the present invention, thewire loops 202-206 are preferably a blackened 34 to 36 gage iron nickelwire having a resistance that changes at a rate of 0.008 ohms/footdegree centigrade (0.026 ohms/meter degree centigrade).

In the particular embodiment illustrated in FIG. 11, the wire loopsextend across the conductive coating 62 between the bus bars 66 and 68,and except for the looped ends 208 of the wire loops 202-206 aregenerally parallel to the bus bars. The wire loops 202-206 arepreferably positioned along the surface of the interlayer 34 overlayingthe conductive coating 62 (see FIG. 1). The wire loops 202-206 areelectrically isolated from the coating 62 so as to insulate thecircuitry of the conductive member 32 from the voltage drop comparatorcircuit 212-216 of the temperature sensor 200 and prevent shorting ofthe circuit. As an alternative, the wires of the wire loops can beprovided with an insulating cover or be embedded within the interlayer34 in a similar manner as the heating wires of the AIR ON system areembedded in the interlayer 34.

With continued reference to FIG. 11, the comparator circuits 212-216monitor the temperature of its respective one of the wire loops 202-206based on the resistance of the wire of the wire loops which changes asthe temperature of the conductive coating 62 of the heatable member 32changes. When the average temperature of any one of the wire loops202-206 reaches a set value, the circuit 212-216 will interrupt thepower from the power supply 72 to the bus bar 68, or set an alarm orsignal that the temperature of the conductive member 62 is rising andcorrective action is recommended. For a detailed discussion of a circuitthat can be used in the practice of the invention, but not limiting tothe invention, attention is directed to U.S. Pat. No. 4,894,513.

As can now be appreciated, the comparator circuits 212-216 can bepositioned in the console 88 (see FIG. 18A).

The invention also contemplates a retrofit arrangement that can be usedto prevent over heating of aircraft transparencies that have heatablemembers, e.g. but not limited to the invention, similar to the heatablemember 32. With reference to FIG. 2, in one non-limiting embodiment ofthe invention, a controller 230 (shown in phantom in FIG. 2) is mountedexternal of the windshield 20 (see FIG. 1). The controller 230 includesan ohm-meter to measures the resistance of the bus bars 66 and 68 and acomparator. When the resistance as measured by the ohm-meter exceeds apredetermined value a signal is sent by the comparator along wire 232(shown in phantom) to open the switch 73 to stop the flow of currentfrom the power supply 72 to the bus bars 66 and 68.

Moisture Sensor

As discussed above and as shown in FIG. 1, the windshield ortransparency 20 has an outboard moisture seal 36 that is a barrier toprevent moisture from entering between the glass sheets 22, 24 and 60,and the plastic interlayers or sheets 26, 28, 30 and 34 of thewindshield 20. More particularly, when the moisture seal 36 fails, e.g.cracks or de-bonds due to erosion caused by wind and rain, moistureenters between the sheets of the windshield. While the cracking orde-bonding of the moisture seal is not a structural issue, when moisturemoves between the sheets, the windshield 20 can de-laminate, and/or theheating arrangement can be damaged and fail, reducing the service lifeof the windshield. When de-lamination of the windshield 20 occurs, therate and amount of moisture entering between the sheets increases,accelerating the degradation of the windshield. As can be appreciated,it would be advantages to monitor the condition or performance of themoisture barrier 36, and replace or repair the moisture barrier beforedegradation of the windshield caused by moisture penetration begins oraccelerates.

With reference to FIGS. 12-14 as needed, there is shown one non-limitingembodiment of the invention having moisture sensors 250-253 positionedon the conductive coating 62 adjacent the sides 78-81, respectively ofthe conductive coating 62 as shown in FIG. 12. Each of the sensors250-253 include a layer 256 of a moisture sensitive electricallyresistant material (hereinafter also referred to as “moisture sensitivelayer”) deposited on the conductive coating 62, and an electricallyconductive layer 258 deposited over the moisture sensitive layer 256(see FIG. 14). Each of the conductive layers 258 of each of the sensors250-253 are individually connected to a positive pole of a DC powersource, e.g. the power source 72 by way of a wire 260A-D, respectively.Optionally the wires are individually connected by way of wire 260A-D,respectively to the positive pole of the DC power source 72 through areostate or variable transformer in a similar manner as the impactsensors 83A-D are connected to the power source 72 (see FIG. 4) toregulate the power input to each of the conductive layers 256 of thesensors 250-253. The invention is not limited to the material of themoisture sensitive layer 256 and any moisture sensitive electricallyresistant material can be used in the practice of the invention, e.g.but not limited to titanium dioxide, and/or the materials disclosed inU.S. Pat. Nos. 4,621,249 and 4,793,175, the disclosures in theirentirety are hereby incorporated by reference. Further the invention isnot limited to the material of the electrically conductive layer 258over the moisture sensitive layer 256 and any electrically conductivematerial, e.g. but not limited to aluminum, copper, gold and silver canbe used. The sensors 250-253 in one non-limiting embodiment of theinvention are elongated members as shown in FIG. 12 including aconductive coating 62 of indium tin oxide, a moisture sensitive layer256 of sputtered titanium dioxide film and an electrically conductivelayer 258 of sputtered gold (see FIG. 14).

As the moisture sensitive layer 256 absorbs moisture, the resistance ofthe moisture sensitive layer 256 decreases. As can be appreciated, theresistance of the layers 256 can be measured and/or monitored in anyusual manner. In one non-limiting embodiment of the invention, wires262A-D are connected to the conductive layers 258 of the sensors250-253, respectively. The voltage difference between each pair of wires260A and 262A, 260B and 262B, 260C and 262C, 260D and 262D is measuredand/or monitored by comparator 270 (see FIG. 13). With reference to FIG.13, the wire 260 of each of the sensors 250-253 is connected tocomparator 270. The comparator 270 monitors the resistance of themoisture sensitive layer 256 of each one of the sensors 250-253. Whenthe voltage difference exceeds a predetermined amount, a signal isforwarded along wire 272 to an alarm or monitor. As can now beappreciated, the comparator 270 can be positioned in or be a part of theconsole 88 (see FIG. 18A).

In the non-limiting embodiment of the invention shown in FIGS. 12 and14, the positive pole (+) of a power source, e.g. but not limiting tothe invention, the power source 70 (see FIG. 2) has its positive pole(+) connected to the conductive layer 258 of each of the sensors 250-253by wire 260A-D, respectively and the negative pole (−) connected to theconductive coating 62 of the heatable member by the wire 70 connected tothe bus bar 66. Adjacent ends of the layer 258 of the sensors 250-253shown in FIG. 12 are spaced from each other a sufficient amount toprevent a current from arcing between adjacent ends of the sensors250-253 and bus bars 66 and 68.

As can be appreciated, in the non-limiting embodiment of the inventionshown in FIGS. 12 and 14, the sensors 250-253 are operational whencurrent is moving through the conductive coating 62. However, in theevent it is desired to have the moisture sensors operational at alltimes, the non-limited embodiment of the invention shown in FIG. 15 canbe used. The embodiment of sensor 274 in FIG. 15 is similar to theembodiment of the sensor 251 shown in FIG. 14 except that the sensor 274includes an electrically non-conductive layer, e.g. a plastic film 276applied over the conductive coating 62, and an electrically conductivelayer 278 similar to the layer 258 over the plastic film 278 and inelectrical contact with the moisture sensitive layer 256. In theembodiment shown in FIG. 15, the wires 260A and 280 are connected to thepower supply, and the wire 278 is connected to the comparator 270 (seeFIG. 13).

In the event it is desired to have a moisture sensor of the invention onone or more of the sheets, e.g. but not limited to the sheet 24 of thewindshield 20, and on the uncoated surface 92 of the sheet 80 (see FIG.2), the embodiment shown in FIG. 16 can be used. The embodiment ofsensor 280 shown in FIG. 16 is similar to the sensor 274 shown in FIG.15 except that the plastic film 276 of the sensor 274 is eliminated. Asshown in FIG. 16, the urethane interlayer 30 covers the glass sheet 24and the moisture sensor 280.

Shown in FIG. 17, is another non-limiting embodiment of a moisturesensor of the invention designated by the number 282. The sensor 282includes a pair of comb electrodes 284 and 286 electrically connected tothe moisture sensitive layer 258. Wires 288 and 290 electrically connectthe electrodes 284 and 286 respectively to an electrical power supply.As can now be appreciated, the invention is not limited to the designand/or construction of the moisture sensor and any of the designs and/orconstruction of moisture sensors known in the art, e.g. but not limitedto those disclosed in U.S. Pat. Nos. 4,621,249; 4,793,175, and 5,028,906can be used in the practice of the invention. The entire disclosures ofthe patents are hereby incorporated by reference.

As can be appreciated, the invention is not limited to the number orarrangement of moisture sensors or detectors positioned on the sheets22, 24, 26, 28, 30, 34 and 60 of the windshield 20. For example and notlimiting to the invention, the moisture sensor can be a single stripthat extends around the margin of one or more of the sheets as shown forthe conductive strip 89 of the crack sensor or detector (see FIG. 5), orthe moisture sensor can be an elongated strip along each side of thesheets as shown for the moisture sensors 250-253 shown in FIG. 12, orthe moisture sensors can have the arrangement shown in FIG. 7 for theconductive members 136, 137, 138, 139, 146, 147, and 150 of the cracksensor.

In another non-limiting embodiment of the invention, the moisture sensorcan be used as a crack detector. More particularly, when the moisturesensor, e.g. the moisture sensor 274 shown in FIG. 15 fractures andseparates, current no longer moves through the electrically conductivelayers 258 and 278 (see FIG. 15) which can be an indication of a crackin the sheet 22, 24 an/or 60 associated with the moisture sensor.

Control System

With reference to FIG. 18, there is shown one non-limiting embodiment ofthe invention to monitor the performance of the transparency 20 of theinvention and to timely schedule maintenance of, e.g. repairs to, orreplacement of, transparencies, e.g. aircraft windshields that areperforming outside acceptable limits. The windshield 20 of the inventioncan have one or more of the impact, rupture, arcing, temperature and/ormoisture sensors or detectors, e.g. but not limited to the typesdiscussed above. With reference to FIG. 18A, the wires from the sensorshaving signals carrying data regarding the performance of components ofthe windshield are connected to one part of a connector, e.g. anelectrical output connector 300. The output connector 300 is notlimiting to the invention and can be any of the types used in the art toprovide external electrical access to an electric device embedded withina laminate. The output connector 300 is connected to an input electricalconnector 302, e.g. other part of the connector, connected to theconsole 88 by a cable 304. In one non-limiting embodiment of theinvention, the console 88 includes a computer having software to readand analyze the signals from the sensors or detectors to monitor and/ordetermine the performance of the components of the windshield. Monitor306 provides visual display, and speaker 308 provides audibleinformation regarding the performance of the windshield, and/orindividual components of the windshield. The console 88 can include analarm 310 to bring attention to the monitor 306. Placing the console 88in the aircraft provides the personnel within the aircraft with realtime performance of the windshield.

In another non-limiting embodiment of the invention, the console 88 hasa wireless transmitter and receiver 312; the transmitter 312 transmitssignals 314 to a transmitting tower 316. The signals 314 carry data onthe performance of the windshield 20. The tower 316 transmits a signal318 carrying the data on the performance of the windshield 20 to asatellite 320. The satellite 320 transmits a signal 322 carrying thedata on the performance of the windshield to a control center 324. Thedata received is studied and the appropriate action to be taken isscheduled. In one non-limiting embodiment of the invention, based on theinformation received, personnel at the control center determine whataction, if any, is needed. If action such as repairs to the windshieldor replacement of the windshield, is needed, a signal 326 providing arepair schedule is transmitted to the satellite 320. The satellite 320transmits a signal 328 having the repair schedule to the tower 316. Thetower 316 transmits a signal 330 having the repair schedule to theconsole 88 and to a maintenance center 332 geographically close to thedesignated repair location (usually the next scheduled stop for theaircraft) to arrange to have all parts, equipment and personal need atthe designated repair location.

In one non-limiting embodiment of the invention, if the data from thesensors indicate that the windshield 20 has to be replaced, the repairschedule can include shipment of the windshield to the next scheduledstop of the aircraft; if the windshield has to be replaced with someurgency, the repair schedule would include a change to the flight planto land immediately and a windshield will be there, or will arriveshortly. The passengers can optionally be transferred to another plane,or wait until the repair is completed. If a repair is scheduled, and therepair can be made without removing the windshield, the repair schedulecan provide for personnel and repair parts to be provided at thedesignated repair location.

As can be appreciated, the invention is not limited to wirelesstransmission of signals carrying information and the transmission can bemade by and lines. Further, the signals can be transmitted betweenlocations solely by satellite, or solely by transmission towers, and bycombinations thereof.

The invention is not limited to the embodiments of the inventionpresented and discussed above which are presented for illustrationpurposes only, and the scope of the invention is only limited by thescope of the following claims and any additional claims that are addedto applications having direct or indirect linage to this application.

1. (canceled)
 2. The method according to claim 21 wherein the vehicle isan aircraft and the monitoring operating performance of the at least oneproperty of the transparency comprises providing the transparency with asensor to monitor operating performance of the at least one property ofthe transparency and to provide a signal having operating performance ofthe at least one property.
 3. The method according to claim 2 whereinthe signal is a first signal, and further comprising forwarding thefirst signal to a first monitoring system positioned in the aircraft,and transmitting a second signal to a second monitoring systempositioned outside of the aircraft, wherein the second signal comprisesinformation from at least one item from the group of items comprisingthe first signal, the acceptable operating performance of the at leastone property, and combinations thereof.
 4. The method according to claim3 wherein the aircraft is a first aircraft and the second monitoringsystem also receives information regarding operating performance of aproperty of a transparency mounted in a second aircraft.
 5. The methodaccording to claim 3 wherein the scheduling repair or replacementcomprises the second monitoring system monitoring the relationship ofacceptable operating limits of the at least one property and theoperating performance of the at least one property of the transparencyto determine a time period in which repair or replacement of thetransparency should be made; designating the geographical work area;arranging for the aircraft, personnel, equipment and/or parts to beavailable at the geographical work area.
 6. (canceled)
 7. The methodaccording to claim 3 wherein the second signal is transmitted to thesecond monitoring system by transmitting the second signal from theaircraft to a first receiving and transmitting tower, or to a receivingand transmitting satellite, and transmitting the second signal from thereceiving and transmitting tower, or receiving and transmittingsatellite, to the second monitoring system.
 8. The method according toclaim 7 wherein forwarding the schedule comprises providing a thirdsignal transmitting information having at least one of the itemsselected from the group of items comprising the time period in which therepair to, or replacement of, the transparency should be made;designating the geographic work area; arranging for the aircraft,personnel, equipment and/or parts to be available at the geographic workarea to repair or replace the transparency, and transmitting the thirdsignal from the second monitoring system to at least one of thefollowing: the aircraft, a third monitoring system, a fourth monitoringsystem, and combinations thereof.
 9. The method according to claim 8wherein the third signal is transmitted from the second monitoringsystem to the receiving and transmitting satellite, or to a receivingand transmitting tower, and transmitted from the receiving andtransmitting satellite, or transmitting and receiving tower to at leastone of the following: the aircraft, the third monitoring system, thefourth monitoring system, and combinations thereof.
 10. The methodaccording to claim 8 wherein the third signal is transmitted to thethird monitoring system, and further comprising acting on theinformation provided by the third signal to arrange for the personnel,equipment and/or parts to repair or replace the transparency to beavailable at the geographic work area.
 11. The method according to claim10 further comprising transmitting the third signal to the fourthmonitoring system wherein the fourth monitoring system is located at thegeographic work area.
 12. The method according to claim 3 wherein thetransparency is an aircraft laminated windshield having two or moreglass and/or plastic sheets.
 13. The method according to claim 12wherein the sensor is selected from the group of a sensor for detectingmoisture; a sensor for detecting impacts to, or vibration of, thewindshield; a sensor for detecting a fracture in one of the sheets; asensor for detecting electric arcing; a sensor for detecting temperaturechanges of an electrically conductive member, and combinations thereof,wherein the sensor is mounted on a surface of one of the sheets betweenfirst and second outer major surfaces of the transparency. 14.(canceled)
 15. The system according to claim 21 wherein the vehicle isan aircraft, and the sensor is mounted on the transparency, wherein thefirst data processing apparatus receives the first signal, and thesecond data processing apparatus generates the second signal andreceives a third signal, wherein the third signal comprises informationfrom at least one item from of the group of items comprising the firstsignal, acceptable operating performance limit of the property, andcombinations thereof.
 16. The system according to claim 15 wherein thesecond data processing apparatus generates the second signal, whereinthe second signal includes information selected from the group of timeperiod in which repair or replacement of the transparency should bemade; designating a geographic area to make the repair to thetransparency or to replace the transparency; arranging for the aircraft,personnel, equipment and/or parts to be available at the geographicarea.
 17. The system according to claim 16 wherein the first dataprocessing apparatus transmits the third signal to a receiving andtransmitting tower, or to a receiving and transmitting satellite, andthe receiving and transmitting tower, or the receiving and transmittingsatellite transmits the third signal to the second data processingapparatus.
 18. The system according to claim 17 wherein the second dataprocessing apparatus transmits the second signal to at least one of thefollowing: the aircraft, a third data processing apparatus, a fourthdata processing apparatus, and combinations thereof.
 19. The systemaccording to claim 18 wherein the second data processing apparatustransmits the second signal to a receiving and transmitting tower, or toa receiving and transmitting satellite, and the receiving andtransmitting tower, or the receiving and transmitting satellitetransmits the second signal to the at least one of the following: theaircraft, the third data processing apparatus, the fourth dataprocessing apparatus, and combinations thereof.
 20. The system accordingto claim 21 wherein the sensor is selected from the group of a sensorfor detecting moisture; a sensor for detecting impacts and vibrations; asensor for detecting fractures; a sensor for detecting electric arcing;a sensor for measuring temperature of an electrically conductivecoating, and combinations thereof.
 21. A method of arranging repair orreplacement of a transparency mounted in body of a vehicle, the methodcomprising: monitoring operating performance of at least one property ofthe transparency; monitoring relationship of acceptable operating limitsof the at least one property and the operating performance of the atleast one property of the transparency; providing the monitoredrelationship to personnel within the vehicle to provide real timeperformance of the at least one property of the transparency; based onthe monitored relationship, scheduling repair or replacement of thetransparency at a geographical area when the monitored relationship isat a predetermined monitored relationship; and forwarding the scheduleto the vehicle and to a maintenance location to prepare for the repairor replacement of the transparency at the designated geographical workarea when the monitored relationship is at the predeterminedrelationship.
 22. A system for arranging repair to, or replacement of, atransparency when a property of the transparency is operating outside ofan acceptable limit, wherein the transparency is mounted in body of avehicle, the system comprising: a sensor to monitor operatingperformance of a property of the transparency, and to generate a firstsignal providing the operating performance of the property of thetransparency, and first data processing apparatus mounted in the vehicleto receive the information of the first signal, to monitor relationshipof acceptable operating limits of the property and operating performanceof the property and to generate a second signal scheduling repair orreplacement of the transparency at a geographical area when theoperating performance as indicated by the first signal is outside anacceptable operating performance limit; a console positioned in thevehicle to receive the first and the second signals and to displayinformation of the first and the second signals to provide real timeperformance of the property of the transparency; and second dataprocessing apparatus positioned outside of the vehicle to receive thefirst and the second signal to prepare for repair or replacement of thetransparency when the monitored relationship is at the predeterminedrelationship.